Craniofacial characteristics are one of the sex determination parameters of age after puberty. The aim of this study is to obtain linear measurements using lateral cephalometric radiography of adults aged 20-40 years based on sex in Indonesia. Ten linear craniofacial parameters on 100 digital lateral cephalometric radiographs were measured. Inter-intra observer reliability was tested using Technical Error Measurement. The independent t-test and the Mann-Whitney U test were used to evaluate the significance of the findings. There are significant differences between males and females on 10 of the linear measurements using lateral cephalometric radiography. Lateral cephalometric radiography showed that the linear measurements of 10 cephalometic parameters were higher in males than females, so it can be used to determine sex. © Published under licence by IOP Publishing Ltd.